fingerd.c revision 1.29 
1/*	$OpenBSD: fingerd.c,v 1.29 2002/09/06 19:43:54 deraadt Exp $	*/
2
3/*
4 * Copyright (c) 1983, 1993
5 *	The Regents of the University of California.  All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 *    notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 *    notice, this list of conditions and the following disclaimer in the
14 *    documentation and/or other materials provided with the distribution.
15 * 3. All advertising materials mentioning features or use of this software
16 *    must display the following acknowledgement:
17 *	This product includes software developed by the University of
18 *	California, Berkeley and its contributors.
19 * 4. Neither the name of the University nor the names of its contributors
20 *    may be used to endorse or promote products derived from this software
21 *    without specific prior written permission.
22 *
23 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
24 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
25 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
26 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
27 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
28 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
29 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
30 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
31 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
32 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
33 * SUCH DAMAGE.
34 */
35
36#ifndef lint
37static char copyright[] =
38"@(#) Copyright (c) 1983, 1993\n\
39	The Regents of the University of California.  All rights reserved.\n";
40#endif /* not lint */
41
42#ifndef lint
43#if 0
44static char sccsid[] = "from: @(#)fingerd.c	8.1 (Berkeley) 6/4/93";
45#else
46static char rcsid[] = "$OpenBSD: fingerd.c,v 1.29 2002/09/06 19:43:54 deraadt Exp $";
47#endif
48#endif /* not lint */
49
50#include <sys/types.h>
51#include <sys/socket.h>
52#include <netinet/in.h>
53#include <arpa/inet.h>
54#include <errno.h>
55
56#include <unistd.h>
57#include <syslog.h>
58#include <netdb.h>
59#include <stdio.h>
60#include <stdlib.h>
61#include <string.h>
62#include <stdarg.h>
63#include "pathnames.h"
64
65void err(const char *, ...);
66void usage(void);
67
68void
69usage(void)
70{
71	syslog(LOG_ERR,
72	    "usage: fingerd [-slumMpS] [-P filename]");
73	exit(2);
74}
75
76
77int
78main(int argc, char *argv[])
79{
80	FILE *fp;
81	int ch, ac = 2;
82	int p[2], logging, secure, user_required, short_list;
83#define	ENTRIES	50
84	char **comp, *prog;
85	char **ap, *av[ENTRIES + 1], line[8192], *lp, *hname;
86	char hostbuf[MAXHOSTNAMELEN];
87
88	prog = _PATH_FINGER;
89	logging = secure = user_required = short_list = 0;
90	openlog("fingerd", LOG_PID, LOG_DAEMON);
91	opterr = 0;
92	while ((ch = getopt(argc, argv, "sluSmMpP:")) != -1)
93		switch (ch) {
94		case 'l':
95			logging = 1;
96			break;
97		case 'P':
98			prog = optarg;
99			break;
100		case 's':
101			secure = 1;
102			break;
103		case 'u':
104			user_required = 1;
105			break;
106		case 'S':
107			if (ac < ENTRIES) {
108				short_list = 1;
109				av[ac++] = "-s";
110			}
111			break;
112		case 'm':
113			if (ac < ENTRIES)
114				av[ac++] = "-m";
115			break;
116		case 'M':
117			if (ac < ENTRIES)
118				av[ac++] = "-M";
119			break;
120		case 'p':
121			if (ac < ENTRIES)
122				av[ac++] = "-p";
123			break;
124		default:
125			usage();
126		}
127
128	if (logging) {
129		struct sockaddr_storage ss;
130		struct sockaddr *sa;
131		socklen_t sval;
132
133		sval = sizeof(ss);
134		if (getpeername(0, (struct sockaddr *)&ss, &sval) < 0) {
135			/* err("getpeername: %s", strerror(errno)); */
136			exit(1);
137		}
138		sa = (struct sockaddr *)&ss;
139		if (getnameinfo(sa, sa->sa_len, hostbuf, sizeof(hostbuf),
140		    NULL, 0, 0) != 0) {
141			strlcpy(hostbuf, "?", sizeof(hostbuf));
142		}
143		hname = hostbuf;
144	}
145
146	if (fgets(line, sizeof(line), stdin) == NULL) {
147		if (logging)
148			syslog(LOG_NOTICE, "query from %s: %s", hname,
149			    feof(stdin) ? "EOF" : strerror(errno));
150		exit(1);
151	}
152
153	if (logging)
154		syslog(LOG_NOTICE, "query from %s: `%.*s'", hname,
155		    (int)strcspn(line, "\r\n"), line);
156
157	/*
158	 * Note: we assume that finger(1) will treat "--" as end of
159	 * command args (ie: that it uses getopt(3)).
160	 */
161	av[ac++] = "--";
162	comp = &av[1];
163	for (lp = line, ap = &av[ac]; ac < ENTRIES;) {
164		if ((*ap = strtok(lp, " \t\r\n")) == NULL)
165			break;
166		lp = NULL;
167		if (secure && strchr(*ap, '@')) {
168			(void) puts("forwarding service denied\r");
169			exit(1);
170		}
171
172		ch = strlen(*ap);
173		while ((*ap)[ch-1] == '@')
174			(*ap)[--ch] = '\0';
175		if (**ap == '\0')
176			continue;
177
178		/* RFC1196: "/[Ww]" == "-l" */
179		if ((*ap)[0] == '/' && ((*ap)[1] == 'W' || (*ap)[1] == 'w')) {
180			if (!short_list) {
181				av[1] = "-l";
182				comp = &av[0];
183			}
184		} else {
185			ap++;
186			ac++;
187		}
188	}
189	av[ENTRIES - 1] = NULL;
190
191	if ((lp = strrchr(prog, '/')))
192		*comp = ++lp;
193	else
194		*comp = prog;
195
196	if (user_required) {
197		for (ap = comp + 1; strcmp("--", *(ap++)); )
198			;
199		if (*ap == NULL) {
200			(void) puts("must provide username\r");
201			exit(1);
202		}
203	}
204
205	if (pipe(p) < 0)
206		err("pipe: %s", strerror(errno));
207
208	switch (vfork()) {
209	case 0:
210		(void) close(p[0]);
211		if (p[1] != 1) {
212			(void) dup2(p[1], 1);
213			(void) close(p[1]);
214		}
215		execv(prog, comp);
216		err("execv: %s: %s", prog, strerror(errno));
217		_exit(1);
218	case -1:
219		err("fork: %s", strerror(errno));
220	}
221	(void) close(p[1]);
222	if (!(fp = fdopen(p[0], "r")))
223		err("fdopen: %s", strerror(errno));
224	while ((ch = getc(fp)) != EOF) {
225		if (ch == '\n')
226			putchar('\r');
227		putchar(ch);
228	}
229	exit(0);
230}
231
232void
233err(const char *fmt, ...)
234{
235	va_list ap;
236
237	va_start(ap, fmt);
238	(void) vsyslog(LOG_ERR, fmt, ap);
239	va_end(ap);
240	exit(1);
241	/* NOTREACHED */
242}
243